And Operator

More complex decisions sometimes require two things to be true. The && operator allows you to check if both operand expressions are true, and then possibly perform some specific action using an if, if-else, or while block.

// Truth table for the boolean AND operator. console.log(true && true); console.log(true && false); console.log(false && true); console.log(false && false);

Examples

Working 9 to 5

Determines if it is currently working hours.

// Determines if it is currently working hours.
var now = new Date();
var hours = now.getHours(); 
var workHours = false;
if (hours >= 9 && hours < 17) {
    workHours = true;
}
console.log(workHours);

Take Your Temperature

Check whether a given temperature is in a healthy range or not.

// Check for temperature in a good range or not.
textLabel("tempLabelID", "What is your temperature?");
textInput("tempID", "");
button("buttonID", "Submit");
textLabel("tempMessageID", "");
onEvent("buttonID", "click", function(event) {
  setText("tempMessageID","");
  var temp = getText("tempID");
  if (temp >= 98 && temp <= 99.5) {
    setText("tempMessageID", "Your temperature is fine.");
  }
  else {
    setText("tempMessageID", "You may be sick.");
  }
});

Syntax

__ && __

Returns

Boolean (true or false)

Tips

• Some complex decisions using an && operator can sometimes be rewritten to use an || operator. It is fine to choose whichever reads clearest.

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